IAV-949/ Add notification system with Zustand global state
Summary
- Introduced a complete notification module (drawer + full page) with synchronized state via a Zustand store
- Notification drawer accessible from the dashboard header with real-time unread count, search, filters (all/unread/read/favorites), and actions (mark read, favorite, archive, delete)
- Notifications page with 4 tabs: send notifications, manage categories, user configuration (channels, types, frequency, advanced), and archives
- Archives tab displays agent avatars and names from the aiAgents data in the agent filter dropdown
- Added notification types, mock data, route, and theme adjustments